Automatic electric connection plug



1 620,185 March 1927 M. c. BERSTED 9 AUTOMATIC ELECTRIO CONNECTION PLUG v Filed Aug. 1923 2 Sheets-Sheet l MWWVCZ 55557-50.

' 1620185 March 8, 1927. M. C BERSTED 9 AUTOMATIC ELECTRIC CONNECTION PLUG Filed Aug. 1923 2 Sheets-Sheet 2 I r M 4 gmwnkoi we T/N 6 5585750.

Patented Mar, 8, 1 927.

MARTIN O. BERSTED, 01E SAN DIEGO, CALIFORNIA.

AUTOMATIC ELECTRIC CONNECTION PLUG.-

Application filed August so, 1923. Serial no. 660,151.

My invention relates to automatic electric connection plugs for electric heating 1 apparatus, and the primaryob ect of my 1nvention is to provide improvements over my previous application for Letters Patent for automatic electric connection plugs filed in the United States Patent Office, April 18, 1923, under Serial No. 632,865. Other objects of my invention are: first, to provide a plug of this class which will automatically connect and disconnect the electrical energy with and from the heating apparatus with which it is used when a predetermined high and low temperature of the same is reached, and which is so constructed that the predetermined high and low temperature of the heating apparatus can be changed as desired by means of a simple temperature regulating means on the plug; second, to provide a plug of this class which has relatively few moving parts, thus reducing to a minimum the cost of manufacture and the chances of the same getting out of order; third, to provide a simple, adjustable, contact making and breaking means for automatic heat regulating devices; fourth, to provide a plug of this class what is substantially fool-proof; fifth, tov provide a plug of this class having auxiliar resilient means in connection with the socket connecting the same with. the terminal osts of a heating apparatus; sixth, to provi e novel reinforcing means for the end of a plug of this class; seventh, to pro- .Vide as a whole a novelly constructed plug of this class, and a plug which as a whole is very simple and economical of construction, durable, reliable, and which will not readily deteriorate or get out of order.

\Vith these and other objects in View, as will appear hereinafter, my invention consists of certain novel features of construction, combination and arrangement of parts and portions as will be hereinafter described in detail and particularly set forth in the appended claims, reference being had to the accompanying drawings and to the characters of reference thereon, which form a part of this application, in which:

Figure 1 is a side view of my automatic electric connection plug secured to one end of an electric cable; Fig. 2 is a fragmentary view thereof, taken at right. angles to that of Fig. 1; Fig. 3 is an end view thereof,

. showing the reinforcing means; Fig. 4 is an enlarged, transverse, sectional view thereof,

taken through 4-4 of Fig. 5; Fig. 5 is an enlarged, sectional view thereof in plan with the section taken through 55 of Fig. 6,

showing the general arrangement of partsand portions; Fig. 6 is a sectional elevational view thereof, taken through 6-6 of Fig. 5, showing certain parts and portions in elevation to facilitate the illustration; Fig. 7 is a transverse, sectional view thereof, taken through 77 of Fig. 5, and Fig. 8 is a fragmentary, enlarged, sectional view thereof, taken through 88 of Fig. 5.

Like characters of reference refer to simi lar parts and portions throughout the several views of the drawings.

The casing members 1 and 2, screw 3, socket member 4, screws-5, reinforcing frame member 6, terminal members 7 and 8, electric cable 9, terminal springs 10, thermostat member 11, rivetslfz, contact members 13 and 14, contact member support 15, pin 16, knob 17, contact plate 18, spring member19, screw 20, cable supporting spring ,21, and the annular member 22, constitute the principal parts and portions of my automatic electric connection plug structure.

i T he casing members 1 and 2, made of hard rubber or other suitable insulating material, are slightly reduced at the ends adapted to be inserted into the socket of the electric heating apparatus, bulged in the middle portion and provided with knob portions 1 and 2 at their opposite ends. Said casing members are secured together near their knob ends by means of a screw 3, and at their opposite ends by means of a reinforcing frame member 6, extending around the edge of said members and backwardly on the sides toward the middle portion. Said reinforcing frame member is provided wit-h a reinforcing portion 6 at its end between the terminal members. Said casing members are also secured together by means of the polygonally shaped socket member 4, positioned between said members intermediate their ends, into which are adapted to be secured the screws 5 from the outer side of the casing members, which screws also extend through the backwardly extending arms of the reinforcing frame member 6 and secure the same in position. Positioned between the casing members 1 and :2 near one end thereof are the sock t terminal members 7 and 8, the

' posts.

i a supporting plate 7 which is provided aterably enlarged at their outer endsto facilitate the introduction ofthe terminal posts of the electric heating apparatus therein. Said terminal members are also slotted backwardly from the outer end to permit a sub.- stantial variation in size 'of the terminal posts of the electric heating apparatus. I have also provided springs 10 on one side of both of said terminal members near their outer ends, which further assist the termi-' nal members to rigidly engage the terminal The elongated, circular recess for the terminal member 8 is provided to take care of slight variations in the spacing of the terminal post of the heating apparatus;

The terminal member 7 is provided with its one edge near one end with a pair of oppositely disposed lugs 7 and 7, to which is riveted the one end of the yieldable thermostat member-11 by means of the rivets 12. The opposite end of the supporting plate 7 is provided with an enlarged portion seated in recesses between said casing members. Said enlarged portion is provided at its middle with an inwardly extending flange 7, which rigidly positions said plate at its one end between said casing members, substantially as shown in Fig. 8 of the drawings. Positioned in the middle portion of the flange of said enlarged portion of the plate 7 is the socket member 4, previously described.

The thermostat member consists of a pair of metallic plates of different co-etficients of expansion, secured together in any conven ient manner. At the free end of said thermostat member is secured a contact member 13, preferably of pure silver, which contact member is adapted to engage a spirally shaped contact member 14 of extended contacting surface, also preferably of pure silver. Said latter contact member 14 is secured to a contact member support 15, as shown best in Fig. 5 of the drawings, said contact member being secured to its sup port preferably by means of welding or brazing. Said contact member support 15 is secured to a pin 16 intermediate its ends, which pin is rotatably mounted at its one end in a conforming recess in the casing member 2. To the other end of the pin is secured the knob 17 by means of a pin 17. Said knob is provided with an enlarged portion 17, which is rotatably mounted in a recess 1 in the casing member 1 and is also provided with a reduced, annular portion 17, which extends through the wall of the casing member 1. Said knob is further provided at its. outwardly extended end with a handle portion 17 the one end of which is preferably pointed in the form of an arrow to indicate the position the knob is to be turned to obtain heat of a certain temperature. Extending around the handle portion 17 of the knob and around the recess through which the reduced portion 17 of said knob extends is a. comically shaped recess 1 which will permit the handle portion 17 to be gripped more easily and at the same time obviate the handle portion 17 from being extended a great distance beyond the casing member 1. Positioned on the 'conically shaped, inclined surface of the casing member 1 are figures indicating tomperatures for adjusting the plug. On the outside of said surface are the letters L, M and H, indicating respectively low,

medium and high temperatures.

The contact member 14 is held in constant frictional engagement with the contact plate 18 through. which the pin 16 also extends and to the opposite end of which is secured the conductor 9 of the electric cable 9 by means of the screw 20, substantially as shown in Fig. 5 of the drawings. Positioned intermediate the contact plate 18 and the recess of the casing member 2 in which the same'is positioned is the spring member 19, which forces the contact plate 18 in engagement 'with the spirally shaped contact member 14, as shown best in Figs. 4, 5 and 6 of the drawings.

An annular spring securing member 22 is positioned in semi-circular recesses 1 and 2", respectively, within the knob portions of the casing members 1 and 2. The electric cable supporting spring 21 extends through circular recesses 1 and 2 in said ends of the casing members 1 and 2 and is secured at its inner end in an annular groove in the annular member 22 by spreading of the spring, substantially as shown in Figs. 5 and 6 of the drawings.

' The operation of my plug is as follows: The plug is mounted on a heating apparatus by the members 7 and 8 engaging the two terminals of a heating apparatus and the current passes to the terminals through the plug as follows: through the conductor 9 supporting member 8* and contact 8 to one terminal, from theother terminal to the contact member 7 then through the mem bers 7 7 thermostat 11, contact 13, contact 14, member 18, terminal screw 20 and conductor 9*. However, when sufficient heat is generated to heat the member 7 sufliciently it will be conducted to the thermostat member 11 which is composed of metals ofdiflerent co-eflicients of expansion which causes the contact member 13 to move away from the contact member ll and thereby open the circuit so that the current is prevented from flowing to the electric heating apparatus. It will be noted that the thermostat operates by reason of the heat of the member 7 which is induced by the terminal of the heating apparatus so that the thermostat operates both by-conduction through the terminal and by radiation from the heating apparatus. 7

It is obvious from this construction as illustrated in the drawings and disclosed in the accompanying specification that there is provided an automatic electric connection plug as aimed at and set forth in the objects of the invention, and though I have shown and described a particular construction, combination and arrangement of parts and portions, I -do not wish to be limited to this particular construction, combination and arrangement, but desire to include in the scope of my invention the construction, combination and arrangement substantially as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a thermostatically controlled electric connection plug, a casing, a plate thermostat member secured at its one end within and at the one end of said casing and provided at its opposite free end with a contact, and a spirally constructed contact member rotatably mounted within said casing adjacent the free end of said contact and adapted to be engaged thereby, the plane of movement of said plate thermostat member and the plane of the spiral of said spirally shaped contact member being arallel with each other permitting a maximum contact between the contact of said thermostat memher and the contact portion of said spirally shaped contact member at all times.

An automatic electric connection plug, including a casing, a thermostat member positioned in said casing, a contact member shiftable by said thermostat member, another spirally constructed contact member rotatably mounted within said casing, adapted to be engaged by said first mentioned contact member, means adapted to connect said latter contact member with an electric cable, and resilient means forcing said latter contact member in positive engagement with said connecting means.

3. An automatic electric connection plug, including a casing, a thermostat member positioned in said casing, a contact member shiftable by said thermostat member, another contact member movably mounted within said casing and provided with an extended engaging surface adapted to be engaged by said first mentioned contact member, means adapted to connect said latter contact member with an electric cable, and resilient means forcing said latter contact member in positive electrical engagement with said connecting means.

- at. In a thermostaticallycontrolled electric connection plug, a casing having a pair of terminals at its one end, a plate thermostat member secured at its one end to one of said terminal members and free at its opposite end, a contact secured to the one side of the free end of said thermostat member, and a spirally shaped contact member rotatably mounted within said casing adjacent the free end of said thermostat member and adapted to be engaged by the contact thereof. In testimony whereof, I have hereunto set my hand at San Diego, California, this 24th day of August, 1923.

MARTIN C. BERSTED. 

